Dynamic-mechanical behaviour of anisotropic magneto-sensitive elastomers

摘要

The low-frequency dynamics of magneto-sensitive elastomers (MSEs) with chain-like and plane-like distributions of magnetic particles is studied under a uniform magnetic field. In this study we continue our previous work [Ivaneyko D. et?al., Soft Matter, 2015, 11, 7627–7638], in which a coarse-grained cubic network model was proposed for description of the dynamic-mechanical behaviour of isotropic MSEs. Presently, to describe the dynamics of MSEs with anisotropic particle distributions, we use a tetragonal lattice model, in which average distances between neighbouring particles along and perpendicular to the symmetry axis of an MSE may differ. Effects of the elastic network and magnetic interactions between the magnetic particles on the dynamics are taken into account. Application of the magnetic fieldHalong the symmetry axis of MSE leads to a strong anisotropy of the dynamic storageG'and lossG″moduli, which depend on the geometry of the applied shear strain with respect toH. The change of dynamic moduli under the magnetic field is more pronounced for MSEs with anisotropic particle distributions as compared to isotropic MSEs.G'andG″can change up to several orders of magnitude in agreement with recent experiments.